If you're interested in a long course in poetic expansion, Ginsberg has a free one. His insights into the Russian Futurist is illuminating and instructive beyond anything I've encountered so far--I think it's his knowledge of the American police state and contact with Russian authors that lend to the insight. He has an amazing collection of original readings that he plays for the class--great stuff:

http://www.openculture.com/expansive_poetics_by_allen_ginsberg_a_free_course_from_1981

The Tempest lectures are a must hear also, though I think he misses some of Shakespeare's subtlety, he manages to capture some interesting lines and give some new insight into the work.